什么是从属连接（subordinating conjunctions）句型？
掌握从属连接句型不仅能帮助您写出复杂的句子，而且句式会更多元，同时避免写出零散的片段短句。从属连接句型能在概念间制造不对等的强调，一方面用主句强调主要概念，另一方面将次要概念放在从属子句（即从句），作辅助陪衬。
一般来说，从属子句通常以从属连接词开头。
什么是子句？
一个完整的句子基本组合会包含主句和从属子句。你可能会问："他们有什么不同呢？为何要分别？"两者最大的差异在于主句本身就可以表达完整的意思，而从属子句则不一定。
首先，让我们简单说一下什么是子句。子句指主语+谓语的结构，它可能是句子的一部分或句子本身。请看以下例句：
Michael laughed. => Michael笑了。（"Michael" 是主语；"laughed" 是谓语；此子句已经是一个完整的句子。）
Michael laughed because Sarah made a funny face. => Michael因为Sarah扮了个鬼脸而笑了。（"Michael laughed" 成为子句，构成句子的一部分。）
子句可以进一步分为主句和从属子句。下面我们将更详细的带您了解两者的区分及用法，一起来看看吧！
主句
主句是包含主语和谓语的短句，且已经表达了完整的逻辑，所以主句可以单独存在。
Steven completed the proposal. => Steven完成了提案报告。
Dennis vacuumed the floor before eating. => Dennis吃饭前先吸了地。
从属连接词
- 对比：although, even though, while（虽然）
- 因果：because, since, as（因为）
- 时间：when（当……的时候）, whenever（无论何时）, while（当……时）, once（一旦）, before（在……之前）, after（在……之后）, since（自从）, until（直到）, as long as（长达）, as soon as（一……就）
- 条件：if（若）, when（当……的时候）, provided that（假若）, in case（假使）, assuming that（假定）, as long as（只要）
- 地方：where（在……哪里）, wherever（无论何处）
- 否定条件：unless（除非）
- 选择条件：whether or not（是……或不是）
从词义上大概可看出，从属连接句型是用来创造次于主句的从属子句；在这类句型中，主句强调主要概念，次要概念则放在从属子句中，作辅助陪衬。至于决定主要、次要概念则看作者的意图，无论句中哪一个概念转为从属子句均会改变句子的重点。请看以下例句：
As I continued to explain my reasoning, my subconscious thoughts became clearer.
Although my subconscious thoughts became clearer, I continued to explain my reasoning.
在第一句里，"我的潜意识"是强调的重点，第二句则强调"我继续解释我的思考逻辑"。从属子句和主句以逗号作区隔，单一从属子句仅是句子片段，并非完整句。例如："Although my subconscious thoughts became clearer" 便不是一个完整的句子。合并主句和从属子句的范例（有下引线的为主句）：
Even though I am not exactly a fan of Lady Gaga, I could not pass on a free concert ticket.
Since becoming a father, I have not slept for more than six hours a day.
透过概念的从属化使句子有重心
假设一个句子内包含两个不同概念，在比较过后可将不重要的概念转为从属子句。
一个具备主要和次要概念的句子可作为良好的论文陈述基础，因为这样的句子能暗示论文的重点并透露观点背后的逻辑推导。将某些概念转为从属子句也有助于加强句子和段落间转折的流畅性。
假设您要合并这两个概念：
Fewer and fewer fish are left in the ocean.
An increasing number of fishermen fish during the bleak winter months.
您可将以上两个句子合并来强调"渔夫越来越多"（主要概念）：
An increasing number of fishermen fish during the bleak winter months, so fewer and fewer fish are left in the ocean.
您也可以在合并句子时，将"鱼越来越少"的事实作为主要概念：
Fewer and fewer fish are left in the ocean because an increasing number of fishermen fish during the bleak winter months.
在这两个例子中，主要概念都可独立作为一个完整句子，而次要概念以从属连接词 "so" 和 "because" 开头，暗示主句与从属句之间的因果关系。
控制句子重点
我们常在不经意间使用了从属和对等连接句型；举例来说，如果要描述某事发生是因为另一件事所造成，例如："David broke his leg while riding a scooter" 或 "David broke his leg when he crashed his scooter into a telephone pole"，可以用几个独立短句或一个从属连接句型表达。
以两个独立短句呈现：
David broke his leg while riding his scooter this weekend. His leg broke when the scooter hit a telephone pole.
用一个从属连接句呈现：
This weekend, David broke his leg when his scooter hit a telephone pole.（"David跌断腿"是主旨，"这件事在摩托车撞到电线杆时发生的"则是从属的句意。）
当在讨论假期要做的两件事时，常会很自然地使用对等连接。这两件事能以分开的独立短句呈现或以一个对等连接句型表示两件事同等重要。
以两个独立短句呈现：I am planning to go to Fuji Mountain when I visit Japan. I am also going to go to Osaka.
以一个对等连接句型呈现：When I visit Japan, I am planning to go to Fuji Mountain and Osaka.
从属连接错误
请避免以下两种常见的从属连接错误：一、将主旨放在从属子句中；二、一个句子中出现过多从属子句。
将主旨放在从属子句中的错误示范：
Gastown, a charming town featuring great art galleries, restaurants, cafés, and shops, is located in Vancouver.
这句的问题在于将主旨嵌在从属子句中，不但没有凸显出煤气镇的特色，反而使次要信息—煤气镇位于温哥华—成为句子重点。以下是修改的范例：
Gastown, located in Vancouver, is a charming neighborhood featuring great art galleries, restaurants, cafés, and shops.
若一个句子有太多从属子句会造成阅读困难，切记需避免。
错误示范：
University professors, who make decisions about which textbook chapters to ignore and which to extend, need to consider more than their individual opinions so that they do not throw out great textbooks they do not recognize as good when they see them, while balancing the need to maintain a course that appeals to a broad class, considering that new textbooks do not yet have a broad following.
修改范例：
University professors need to consider more than their individual opinions when they decide which textbook chapters to ignore and which to extend. Many years ago, some of these very professors decided that currently popular textbooks should be thrown out, clearly demonstrating that they do not always know which books would become great. University professors should also balance the need to maintain a course that appeals to a broad class with an appreciation for new textbooks that do not yet have a broad following.
